Signs showing the status of the location where the sign is placed take many configurations. Probably the most popular is the "OPEN-CLOSED" sign used in retail establishments. When the store opens, a clerk turns the sign to display "OPEN" printed on one side. When it closes, the sign is turned over to display "CLOSED". While in widespread use, the signs are subject to considerable wear in being turned over at least twice each business day. Moreover, they are unattractive and are not visible for a very great distance from the sign.
For many years, people have been trying to display alternative messages with signs that slide between one of two modes. However, virtually all of them switch from one message to another printed at separate locations on the sign. Thus, U.S. Pat. Nos. 2,897,6l7; 3,111,782; 3,748,767 and 4,217,713; British Nos. 441,846 and 1,176,837; and French No. 745,356 all operate in this way.
The drawback of all of these signs is that they are not compact. Thus, "OPEN-CLOSED" requires at least 12 spaces in width in the two British patents, and considerably more in U.S. Pat. Nos. 3,748,767 and 4,217,713. This means that a sign on the office of a gas station, for example, to be visible to motorists in the street, would have to be extremely large. The prior art signs have not generally been designed for compactness.
One sign that is compact is shown in U.S. Pat. No. 4,485,576. While it shows "OPEN-CLOSED", it does so in odd-shaped apertures, arrows and a confusing display that requires exceedingly careful registry.
There is a need for a compact sign that reuses information displayed on spaces and apertures of the same size so that registry problems and non-essential displays are avoided, while at the same time one of two alternate messages is displayed.